1. Field of the Invention
The present invention relates to a semispherical shoe formed into a substantially semispherical shape by a convex semispherical surface and a flat end surface, and a manufacturing method therefor. More particularly, it relates to a semispherical shoe in which the semispherical surface has a slidably contacting surface that is in slidable contact with a semispherical concave portion and a non slidably contacting surface that is not in slidable contact with the concave portion, and a manufacturing method therefor.
2. Background of Related Art
Conventionally, as a semispherical shoe used for a swash plate compressor, a semispherical shoe has been known which is formed into a substantially semispherical shape by a convex semispherical surface and a flat end surface, the semispherical surface having a slidably contacting surface that is in slidable contact with a semispherical concave portion and a non slidably contacting surface that is not in slidable contact with the concave portion (Patent Document 1). Patent Document 1: Japanese Patent Laid-Open No. 2001-153039
The semispherical concave portion provided in a piston of the swash plate compressor is generally formed so as to have the same curvature. On the other hand, the slidably contacting surface that is formed in the semispherical surface and is in slidable contact with the concave portion is formed into a ring shape in an intermediate portion between the top portion of semispherical surface and the end surface so as to surround the top portion, and is formed so as to have the same curvature as that of the semispherical concave portion.
In other words, the non slidably contacting surface that is not in slidable contact with the concave portion is formed at two places on the top portion side of semispherical surface and the end surface side, and the slidable contacting surface is formed in an intermediate portion therebetween.
The non slidably contacting surfaces at two places cannot be formed so as to have the same curved surface as that of the slidably contacting surface because they must not be in slidable contact with the concave portion. As a result, the semispherical surface has at least the curvature forming the non slidably contacting surface on the top portion side of semispherical surface, the curvature forming the slidably contacting surface, and the curvature forming the non slidably contacting surface on the end surface side of semispherical surface. In order to manufacture the semispherical surface having such a complicated curvature, the manufacturing process therefor must be complicated inevitably.
Also, since the manufacturing process is complicated, it is difficult to stably secure the width of the slidably contacting surface extending in the circumferential direction of semispherical surface in all of the semispherical shoes, and there is a danger of seizure because the surface pressure increases with a decrease in the width of slidably contacting surface.
The present invention has been made in view of the above circumstances, and accordingly an object thereof is to provide a semispherical shoe having a configuration capable of stably securing the width of slidably contacting surface in all of the semispherical shoes, and a manufacturing method for the semispherical shoe.